High Power CSP Thermal Solutions

With electronic package tends to be lighter, thinner and smaller, Chip scale packages (CSP) become more and more popular for portable electronic products like notebooks, mobile phones, PDAs, digital cameras, etc. For CSP, the die size occupied 80% or above of the package size, so the package profile can be as small as possible to possess better electrical performance dues to shorter interconnections. However, tins shrinking on package profile limits heat spread and causes over heat concentrating on package, which becomes a primary challenge for CSP designers. In this paper, we provide a thermal solution for CSP considering package structure, substrate structure and heat spreader structure using design of experiment (DOE) method for optimized package solution. From DOE simulation results, embedded heat spreader structure can perform best thermal performance, which has about 9% thermal improvement compare to typical TFBGA package. Moreover, experiment validations were also conducted and have good agreement with simulation results. Finally, thermal characteristic for embedded heat spreader TFBGA with really application setting on hard disk drive (HDD) was also investigated.